The present invention relates to ski bindings in general and in particular to releasable ski bindings having a mechanism by which entry into the binding is effected simply by stepping into the binding. Such bindings are commonly called step-in bindings.
In its simplest form, a releasable binding comprises one or more movable clamping members for releasably engaging one or more clamp-receiving members. The movable clamping members may be on the ski and the clamp-receiving members on the boot; or, alternatively, the location of the members may be reversed. To each of the movable clamping members there is coupled a mechanism, sometimes called a force unit, for applying a clamping force to the member. The mechanism for applying the clamping force to the movable clamping member may take several forms. One of the most common forms is a spring member. The spring member is particularly useful because it is relatively easy to use for applying a resilient clamping force to the movable clamping member. This is important for providing shock absorption and force adjustment. However, other mechanisms, such as electrical, magnetic, etc., may also be used for providing the necessary clamping force. Included among releasable bindings of the type referred to are the familiar toe-heel binding and the more recent side-clamp binding.
In the conventional toe-heel binding a clamping member is provided for clamping the toe and heel portions of a ski boot to a ski. In the conventional side-clamp binding there is provided a movable lateral clamping member for clamping the sides of a ski boot to a ski rearward of the toe and forward of the rear of the heel of the boot.
To facilitate clamping a ski boot to a ski, various step-in mechanisms have been proposed and incorporated in both the toe-heel and side-clamp type ski bindings.
In the conventional toe-heel type ski binding the step-in mechanism which allows a skier to step into a binding comprises a clamping member which is set to receive or is pre-loaded by a clamping force and is generally located at the rear and forms an integral part of the ski boot heel-clamping portion of the toe-heel binding. Typically the heel step-in mechanism is an overcenter type mechanism. In the mechanism a member is provided which extends forwardly of the mechanism to be engaged by the heel of a ski boot. To cock the mechanism and apply the clamping force to the clamping member, the forwardly extending member is moved to a raised position as by a strap, lever member or the like. As the heel of the ski boot is brought to bear thereon, the forwardly extending member is moved overcenter to a lower position wherein the full clamping force is applied to the heel of the ski boot for clamping the ski boot between the heel and toe clamping members. Manual cocking or resetting of the step-in mechanism is typically required prior to each re-entry of the binding.
In the side-clamp type binding, the step-in mechanisms which heretofore have been proposed are located at the heel of the ski boot or in a position to be contacted by the sole of the ski boot generally rearward of the toe and forward of the rear of the heel of the boot.
In the side-clamp type binding in which the step-in mechanism is located at the heel of the ski boot, there is provided, as in the conventional toe-heel type step-in binding, a member which extends forwardly of the mechanism to be engaged by the heel of the ski boot. As in the conventional toe-heel binding, to cock the mechanism and apply the clamping force to the clamping members, the forwardly extending member is moved to a raised position as by a strap, lever member or the like. In one such binding, to manually cock the binding, a force unit comprising a spring member is moved to a position wherein the force of the spring member is removed from the clamping members. When the force of the spring member is removed from the clamping members in this type of binding, the step-in mechanism, which is itself spring-loaded, is moved by its spring to engage a part of the clamping member. After the step-in mechanism engages the clamping member, the force unit is moved to its clamping position. With the force unit moved to its clamping position, the full clamping force of the spring member is restrained by the step-in mechanism from moving the clamping members to their closed or clamping position.
In use, as the heel of the ski boot is brought to bear on the forwardly extending member, the forwardly extending member is moved from its raised position to a lower position. As the forwardly extending member is moved to its lower position, it is disengaged from the clamping member, thereby allowing the clamping member to engage the ski boot or other clamp-receiving means attached to the ski boot with the full clamping force of the spring member.
One of the principal disadvantages of the step-in mechanism of the aforementioned side-clamp type binding is that is is necessary to provide a clearance space in the nature of a cutout in the heel of the boot for the forwardly extending heel-engaging member and parts of the step-in mechanism and force unit rearward thereof. The cutout in the heel portion of the ski boot is required to provide necessary clearance for the parts of this type of step-in mechanism and, in particular, to provide the clearance necessary for the step-in mechanism to automatically reset during involuntary release. Under certain conditions, the binding will cock during a release. A side-clamp type binding of the type described is shown in the German specification Offenlegungsschrift 2,649,826.
In the heretofore proposed side-clamp type step-in binding in which the boot-actuated part of the step-in mechanism is located in a position to be contacted by the sole of the ski boot generally rearward of the toe and forward of the rear of the heel of the boot, there is provided a step-in member which is movably mounted in a hole provided therefore in a housing of the binding. In this step-in mechanism the step-in member is provided with a surface for engaging a facing surface on a part of the movable clamping members. To manually cock the binding prior to entry of a ski boot therein, a force unit comprising a spring member is moved to a raised position for removing the clamping force from the clamping members. With the clamping force removed from the clamping members, the step-in member, which is itself spring-loaded, is moved to a raised position wherein the engaging surface on the step-in member engages the facing surface on the clamping members. Thereafter, as the force unit is moved to its clamping position, the full force of the force unit is brought to bear on the step-in member. The binding at this point is prepared for entry.
To enter the binding, a skier places his or her ski boot in skiing position over the step-in member and, pressing down, moves the step-in member downwardly into the housing. As the step-in member is moved downwardly into the housing, the step-in member disengages from the clamping members, allowing the clamping members to engage the ski boot or other clamp-receiving means with the full clamping force of the force unit.
It is also possible to cock or reset the binding during an involuntary release. This occurs when, during an involuntary release, the clamping members open against the force of the spring member and allow the step-in member to move to its cocked position relative to the housing under the force of its spring member. In either case, when cocked, the full clamping force of the force unit is brought to bear on the step-in member. A step-in binding of this type is described in U.S. Pat. No. 4,063,572, assigned to the applicant of the present application.
In considering the known side-clamp type bindings, with step-in mechanisms, it is seen that both of the prior known type bindings have the disadvantage of having the full clamping force of the force unit applied to the step-in member for a substantial period of time when the binding is cocked. This condition imposes severe mechanical requirements on the various parts of the binding and, in particular, on the mechanical structure of the step-in member and facing surface of the clamping members. The previously described side-clamp bindings with the step-in member located at the heel of the ski boot further suffer from the disadvantage of being more complicated structurally and requiring specially made ski boots having cutouts in the heel portion of the sole thereof for providing clearance for parts of the binding mechanism. In comparison, the side-clamp type binding with the step-in member located in use rearward of the toe and forward of the rear of the heel has a simpler mechanical structure and does not require special ski boots. Also, the latter binding achieves its objectives without interfering with the movement of the ski boot relative to a ski in any direction during shock-absorbing maneuvers or release.